The effects of lattice distortion magnitude on the oxidation performance of laser-cladded NiCoCr-M (M=Al, Fe, Si) multi-principal element alloy coatings under high temperature exposure

Isothermal oxidation kinetic behavior of coating at 1100°C were investigated for the 3 ∼ 6 components multi-principal element alloy coatings of the 10 groups were prepared by laser cladding. The results indicate that adding an appropriate amount of Al and Si content is beneficial in the alloy coating to preferentially form a Al2O3 and Cr2O3 protective scale. As the lattice distortion magnitude of alloy system is rising, the oxidation kinetics constant Kp value of the alloy coating is decreased, it is related to the atomic jump path in lattice matrix. Overall, the hopping path of the atom in the fcc lattice matrix is longer than the bcc. In addition, regarding the Weibull modulus of the hardness statistical value after coating oxidation, indicating that the fcc-alloy is durable at high temperatures than bcc-alloy. This study provides potential contributions to the application of high temperature thermal protection for multi- principal element alloy coatings.